Abstract:To explore the effect of 60Co-γ irradiation mutagenesis on bud breaking of fig one-year-old canes and young shoots of different maturation level,the one-year-old hardwood of three fig cultivars ‘117D’,‘Green Peel’ and ‘110C’,and the young shoots of two fig cultivars ‘108B’ and ‘110C’ were used as the materials.The highest dose of 60Co-γ irradiation were set at 160 J/kg for hardwood cuttings and 200 J/kg for young shoots,bisection decrease was used to make a ladder of irradiation doses.After the treatment the hard wood cuttings were soil rooted and the young shoot cuttings were put in a hydroponic container.The bud breaking rate of the cuttings was observed and calculated.The result showed:Under the dose of 160 J/kg irradiation,all the hardwood cuttings of the three cultivars were died;while very significant difference on cutting bud breaking rates were found between 40 and 80 treatment and among different cultivars.Among the three cultivars,‘117D’ demonstrated the highest tolerance to the irradiation,while ‘Green Peel’ showed the lowest tolerance;For the young shoot cuttings,‘108B’ and ‘110C’ cultivar were all died under 200 J/kg irradiation in regardless their maturation level.Very significant difference on bud breaking rate was revealed with irradiation doses of 50 and 100 J/kg and among three levels of shoot maturation levels revealing that the maturation level of young shoot cuttings was negatively correlated with the irradiation dose tolerance.The tolerance of ‘108B’ young shoot cuttings was higher than that of ‘110C’ cultivar.Further observations demonstrated that irradiation treatments led to delayed bud breaking and repressed root formation of cuttings.In conclusion,for bud mutagenesis irradiation treatment,the suitable 60Co-γ irradiation dose to fig hardwood cuttings was between 40-80 J/kg; for the young shoots,the suitable dose was between 50-100 J/kg;and different fig cultivars display different sensitivity to 60Co-γ irradiation.